A polyethylene-based resin extruded foam sheet (hereinafter also referred to as foam sheet), having an excellent antistatic performance, flexibility, and a shock-absorbing property, is capable of preventing damage and scratches of a packaged article, and has accordingly been widely used as a material for packaging a household appliance, glassware, a ceramic, and the like. Moreover, with the development of, and the increasing demand for, flat panel television and the like in recent years, a foam sheet having an antistatic property has been used as an interleaf sheet inserted between a pair of glass plates to prevent damage to a surface of the glass substrate during packaging and/or transportation of the glass substrate for use in an image display device, such as a liquid crystal display, a plasma display, or an electroluminescence display (Patent Literatures 1 and 2).
Glass plates having various thicknesses have heretofore been developed as a glass plate for use in an image display device such as a liquid crystal panel. Recently, very thin glass plates each having a thickness of about 0.5 mm or less have been manufactured from a viewpoint of weight reduction, energy saving, production cost, and the like. Use of a conventional thick foam sheet having a thickness of from about 1 mm to 2 mm as an interleaf sheet for such thin glass plates not only reduces the load efficiency, but also may damage a glass plate depending on a loading condition due to an excessively large thickness of the interleaf sheet relative to the glass plate.
Accordingly, a foam sheet having a small thickness is being developed as an interleaf sheet suitable for thin glass plates. However, production of a foam sheet having a small thickness presents a problem in that a small hole or a through-hole is readily formed in the foam sheet.
To address such a problem, the present inventors had already developed polyethylene-based resin extruded foam sheets each having an average thickness of 0.5 mm or less by using a unique foam control agent and the like (Patent Literatures 3 and 4).
These polyethylene-based resin extruded foam sheets are of high quality such that formation of a small hole or a through-hole has been reduced or eliminated despite an average thickness of 0.5 mm or less, and have an excellent antistatic performance and a shock-absorbing property.